Apollo and Starbuck discover a strange, magnetic void in space. Meanwhile, two Viper pilots return to the Battlestar Galactica after visiting a nearby planet, and decide to skip the regular decontamination procedures; a virulent disease then begins sweeping throughout the ship, and soon every available Viper pilot has been struck down. Apollo and Starbuck are warned not to return to the Galactica; instead they must instruct the female shuttle and transport pilots on how to fly the highly complex Viper fighters so that they can defend the fleet from the Cylons. Apollo and Starbuck survey the void, and manage to lead the Galactica safely through; here they discover the planet Kobol, which Commander Adama is convinced is the world that man originated from. Hoping that it will provide a clue to the location of Earth, Adama leaves to investigate the planet – unaware that the traitor, Baltar, is helping the Cylons to launch another attack on the Galactica…